feat: llm support

.env.example

@@ -1,17 +1,16 @@
-# .env.example file
-# This file provides examples of environment variables needed for the project.
-# For actual use, you will need to copy this file to create an .env file and enter the actual values.
+# InterviewGraph environment example
+# Copy this file to .env and replace placeholder values.
 
-# Langsmith Project Tracking
-# LangSmith is a tool for monitoring and debugging 
-LANGSMITH_PROJECT=act...  # Project name to be used by LangSmith.
-LANGSMITH_API_KEY=lsv2...  # LangSmith API key (must be replaced with real key)
+# Optional observability
+LANGSMITH_PROJECT=interviewgraph
+LANGSMITH_API_KEY=
 
-# Depending on the configuration you choose, you will need the following environment variables.
+# LLM generation runtime config
+# Supported providers in this repo: openai, anthropic
+INTERVIEWGRAPH_LLM_PROVIDER=openai
+INTERVIEWGRAPH_LLM_MODEL=gpt-4o-mini
+INTERVIEWGRAPH_LLM_TEMPERATURE=0.2
 
-## LLM API Keys:
-# OpenAI API Key - required to use the GPT model.
-# You can get it from the OpenAI website (https://platform.openai.com/).
-OPENAI_API_KEY=sk...
-
-# Others...
+# Provider API keys (set the one matching provider)
+OPENAI_API_KEY=
+ANTHROPIC_API_KEY=

casts/resume_ingestor/modules/models.py

@@ -10,13 +10,48 @@
     - Embedding Models: https://docs.langchain.com/oss/python/integrations/text_embedding
 """
 
-# from langchain.chat_models import init_chat_model
-# from langchain_openai import ChatOpenAI
+from __future__ import annotations
 
+import os
+from typing import Any
 
-def get_sample_model():
-    # return init_chat_model(
-    #     model="",
-    #     model_provider="openai",
-    # )
-    pass
+
+def get_generation_model() -> Any | None:
+    """Returns a configured LangChain chat model, or None if unavailable.
+
+    Configuration (all optional):
+    - INTERVIEWGRAPH_LLM_PROVIDER (default: openai)
+    - INTERVIEWGRAPH_LLM_MODEL (default: gpt-4o-mini)
+    - INTERVIEWGRAPH_LLM_TEMPERATURE (default: 0.2)
+    """
+
+    provider = os.getenv("INTERVIEWGRAPH_LLM_PROVIDER", "openai").strip().lower()
+    model = os.getenv("INTERVIEWGRAPH_LLM_MODEL", "gpt-4o-mini").strip()
+    temp_raw = os.getenv("INTERVIEWGRAPH_LLM_TEMPERATURE", "0.2").strip()
+
+    if not _has_provider_credentials(provider):
+        return None
+
+    try:
+        temperature = float(temp_raw)
+    except ValueError:
+        temperature = 0.2
+
+    try:
+        from langchain.chat_models import init_chat_model
+
+        return init_chat_model(
+            model=model,
+            model_provider=provider,
+            temperature=temperature,
+        )
+    except Exception:
+        return None
+
+
+def _has_provider_credentials(provider: str) -> bool:
+    if provider == "openai":
+        return bool(os.getenv("OPENAI_API_KEY", "").strip())
+    if provider == "anthropic":
+        return bool(os.getenv("ANTHROPIC_API_KEY", "").strip())
+    return False